Marine turbine lubrication



United States Patent 2,991,250 MARINE TURBINE LUBRICATION John F.Socolofsky, Glassboro, N.J., assignor to Socony Mobil Oil Company, Inc.,a corporation of New York No Drawing. Filed Mar. 28, 1957, Ser. No.649,001 2 Claims. (Cl. 25246.7)

and other'parts of the systemwhere the temperature" is relatively low.These insoluble materials may settle out on governor parts, in bearingpassages, in coolers, strainers and oil reservoirs where theiraccumulation can interfere with'the supply of oil to bearings and withgovernor operation. Likewise, severe rusting conditions are encountereddue to contamination of the oil with water from leaking shaft seals,condensation of humid air in the oil reservoir and bearing pedestals,water leaks in oil coolers, etc. Rust formation, ofcourse, is extremelyundesirable for several reasons. Thus, rust particles catalyze oxidationof the oil. Also, rust is abrasive and when carried by the oil to thebearings causes scratching and excessive wear. Furthermore, when carriedinto the small clearances of the governor mechanism, the rust can causesluggish operation and even make the governor stick.

It has therefore, become the practice in the art to fortify marineturbine oils by the addition theretoof chemical additives which enablethese oils to resist oxidation and furnish maximum protection againstrusting. Antioxidants which have been used, for example, 'incl-ude:phenolic-type compounds, particularly alkylated phenols, such as2,6-di-tertiary-butyl-4-methyl phenol, 2,4,6-tri-tertiary-butyl-phenoland the like; aryl amines, such as phenyl-alpha-naphthyl amine,butyl-alpha-naphthyl amine, etc.; and alkylated diphenyl amines, such asoctyldiphenyl amine. v Likewise, a variety of anti-rust agents have beenutilized in turbine oils. One class of such anti-rust agents aretheproducts produced by first reacting a monocarboxylic acid with apolyalkylenepolyamine and then reacting the product so formed with analkenyl succinic acid anhydride. This class of anti-rust agents andtheir manner ofpreparation are fully described in U.S. Patent No.2,568,876, issued September 25, 1951, to R. V. White et al. As shown inthat patent, the monocarboxylic acid is reacted With thepolyalkylenepolyamine in a mole proportion varying between about 1 andabout x-l to 1,

respectively, where x represents the number of nitrogen atoms in thepolyalkylenepolyamine molecule. The alkenyl succinic acid anhydride isthen reacted with the intermediate product in a molar proportion varyingbetween about x1 and about 1 to 1, respectively; the sum of the numberof moles of the monocarboxylic acid and of the alkenyl succinic acidanhydride reacted with each 'tinued under these conditions for threehours. .ti'o'n product had an N.N. of 56.6. The product conice Fivehundred and sixty-four grams (2.0 moles) of distilled oleic acid and 219grams (1.5 moles) of triethylenetetramine were placed in a S-necked,2-liter, roundbottomed flask provided witha stirring device, athermometer and a reflux take-off trap. The trap was filled with benzeneand the reactants were heated with stirring to 142 C. "About 40 ml. ofbenzene was added to the reaction mixture and reflux was maintained forten hours with the flask contents at a temperature of 145 C. A total of58 ml. of an aqueous layer was collected in the take-off trap. Benzenewas removed from the reaction product by the gradual reduction inpressure to to 200 mm. Hg at a flask temperature of C. to C. Theintermediate product so produced had a neutralization number (mg. KOHper gram of sample) of 4.2 and an average molecular weight of 484.

Sixty-three gramsof tetrapropenyl succinic acid anhydride having aneutralization number of (0.214

. 'mole) and 45 grams (0.093 mole) of the above intermediate product,together with 106 grams of diluent oil '(a conventional 100 sec. at 100F. parafiin oil) were charged to a 3-necked, round-bottomed flaskprovided with a stirring device, a thermometer and an outlet tube whichin turn was connected to a manometer, a Dry-Ice trap and a vacuum pump.The flask contents were heated 'with stirring to 100 C. and the pressurewas gradually reduced to 50 mm. of mercury. The reaction was con- Thereactained about 50%, by

agent. a

For some time oils fortified with antioxidant and antirust agents havebeen used successfully for the lubrication of marine turbines and theirreduction gears. However,' with the development of smaller reductiongear sets and consequent heavier loading of gear teeth,,,these'oils havebeen found to be inadequate in that the lubricant film is unable towithstand the, high gear pressures and is ruptured. As a result,scufiing and scoring has occurred which reduces the service life andefliciency of the gears. The art has, therefore, sought to improve theload-carrying ability of turbine oils. Initially, it appeared that thiscould be accomplished simply by incorporating in the oil any one of anumber of additives known to provide extreme pressure characteristics inlubricating oil. It was found, however, that although such additives didincrease the load-carrying capacity of the oil, they also reduced theantioxidant and anti-rust characteristics of the oil to an intolerabledegree. It, therefore, became a problem in the art to provide anadditive which would not only provide extreme pressure properties in theturbine oil, but which at the same time would preserve the necessaryhigh antioxidant and anti-rust characteristics of the oil. The presentinvention is concerned with the provision of such an additive. 'It is,therefore, an object of this invention to provide a marine turbine oilcomposition which possesses not only excellent antioxidant and anti-ruststability, but which also is capable of maintaining a lubricating filmunder the extreme pres: sures encountered in the turbine reductiongears. Other and further objects will become apparent from the followingdescription of the invention.

In accordance with this invention, the above object is weight, oftheactive anti-rust accomplished by the addition to the turbine oil of asmall mole of the polyalkylenepolyamine being no greater than x. Aspecific product of this type is one prepared from oleic acid,triethylenetetramine and tetrapropenyl succinic acid anhydride, thepreparation of which is' illustrated by the following example.

amount of tris-(Z-chloropropyl)-thionophosphate.

As far as is known, tris-(2-chloropropyl)-thionophosphate has not beenproposed heretofore as an extreme pressure agent for lubricating oils.Accordingly, it is considered that the present invention embraces theuse Reissued July 4, 1961 of this material as an extreme pressure agent,not only in turbine oils, but in lubricating oils in general. Theability of tris-(Z-chloropropyl)-thionophosphate as an extreme pressureadditive and particularly its unique ability as an extreme pressureadditive for use in turbine oils in comparison with a number ofcompounds heretofore recognized in the art as extreme pressure additivesis illustrated by the data presented in Table I. This table shows theresults of antioxidant, anti-rust and extreme pressure tests conductedon a typical turbine oil composition containing the usual amounts ofantioxidant and anti-rust additives and on this same turbine oilcomposition having added thereto (a) diiferent known extreme The amountof tris-(Z-chloropropyl)-thionophosphate to be used as an extremepressure agent in lubricating oils, including oxidation andrust-inhibited turbine oils, will range generally from about 0.25% toabout 5.0%, the usual amount being from 1.0% to about 3.0%. Turbine oilsin which the tris-(2-chloropropy1)-thionophosphate is employed maysuitably contain from about 0.05 to about 2.0%, by weight, ofantioxidant and from about 0.01% to about 1%, by weight, of anti-rustagent.

The oil compositions contemplated herein may also contain minor amountsof other additives, designed to improve the properties thereof in otherrespects, such as V.I. improvers, pour depressants, defoamants, etc.

Table l Additive Tris-(Q-chloropropyl)-thionophosphate..Tetrabutylthiuram disulfide.

Tris-(B-chloroethy1)phosphite Dibenzyl disulfide ChlorokeroseneIsopropyl Xanthate Zinc dithiophosphate Chlorinated paraflin wax Cl) 2Benzothiazyl N,N diethyl thiocarbamyl sulfide. Load Tests:

SAE (p.s.i.) Timken (1bs.) Copper Strip Corrosion Test (A.S.T.M.

D 130; 3 Hr. 212 F.):

Tarmsh Rust Test: (A.S.T.M., D-943):

500 HL-NN (2)Mod. (1)Slt... (1)Slt (1)S1t.. (3) Dark.

. Henvy Moderate- Moderate.- None..

0.15 0.15 0.35 0.45 Heavy Moderate.. Moderate Moderate..

1 About one-half of iron coil disintegrated. 9 About three-quarters ofiron coll disintegrated.

pressure additives and (b) tris-(Z-chloropropyD-thioncphosphate.

The turbine oil used as the base oil in all of the tests was a 400" SUVat 100 F., solvent-refined Mid-Continent oil containing 0.25% of2,6-ditertiary butyl paracresol, a commercial antioxidant additive and0.1% of an anti-rust agent prepared from oleic acid,triethylenetetramine and tetrapropenyl succinic acid anhydride after thefashion of Example I, hereinabove.

The procedures employed for the various tests were as follows:

(1) The SAE test was conducted according to CRC Method L-17-545 using amain shaft speed of 500 r.p.m. (CRC Handbook, 1946 edition, pages 458 to462).

(2) The Timken test was conducted according to CRC Method L-18-545 (CRCHandbook, 1946 edition, pages 462 to 466).

(3) The copper strip corrosion test procedure was that of A.S.T.M.Method' D-130 (A.S.T.M. Standards on Petroleum Products and Lubricants.November 1952, pages 81 to 84).

(4) The rust test procedure was that of A.S.T.M. Test Method D-943(A.S.T.M. Standards on Petroleum Products and Lubricants, November 1954,pages 418 to 422).

The results of the various tests are presented in Table I. It will beseen from the table that while all the blends show good load-carryingability, blends Nos. 2 to 6 containing the various commercial extremepressure addition agents and combinations were corrosive to eithercopper or steel or both. In comparison, blend No. 1 prepared withtris-(Z-chloropropyl)-thionophospliate gave complete protection againstoxidation and rust. Of the various agents added to' provideload-carrying ability to the turbine oil, therefore, only thetris-(Z-chloroprbpyl) -thion0- phosphate successfully preserved theantioxidant and antir'ust characteristics of the oil. A

Having now fully described the invention, what is claimed to be new anduseful and desired to be secured by Letters Patent is:

l. A method of lubricating a marine turbine and the associated reductiongears which comprises applying to the relatively moving parts thereof acomposition comprising a major proportion of mineral lubricating oil, aminor proportion, from about 0.05% to about 2%, by weight, of a phenolicantioxidant, a minor proportion, from about 0.01% to about 1%, byweight, of an antirust agent consisting of a reaction product obtainedby reacting a monocarboxylic acid with a polyalkylenepolyamine havingone more nitrogen atom per molecule than there are alkylene groups inthe molecule, in a molar proportion varying between about 1 and aboutx-l to 1, respectively, wherein x represents the number of nitrogenatoms in the polyalkylenepolyamine molecule, to produce an intermediateproduct, and reacting an alkenyl succinic acid anhydride with saidintermediate product, in a molar proportion varying between about x-land about 1 to 1, respectively; the sum of the number of moles of saidmonocarboxylic acid and of said alkenyl succinic acid anhydride reactedwith each mole of said' polyalkylenepolyamine being no greater than x,and a minor proportion, from about 0.25% to about 5.0%, by weight, oftris-(2-chloropropyl)-thionophoshate. p 2. A method of lubricating amarine turbine and the associated reduction gears which comprisesapplying to the relatively moving parts thereof a composition comprisinga major proportion of mineral lubricating oil, a minor proportion, fromabout 0.05 to about 2%, by weight, of a 2,6-ditertiary butyl paracresol,a minor proportion, from about 0.01% to about 1%, by weight, of areaction product formed by reacting about one and one-third molarproportions of oleic acid with 1 molar proportion oftriethylenetetramine to rform an intermediate product and then reactingabout 1 molar proportion of the intermediate product with 2 molarproportions of tetrapropenyl succinic acid anhydride and a minorproportion, from about 0.25% to about 5%, by weight, oftn's-(2-ch1oropropy1)-thionophosphate.

References Cited in the file of this patent UNITED STATES PATENTSPrutton Oct. 31, 1939 Kavanagh Mar. 28, 1944 2 White Sept. 25, 1951Smith Nov. 1, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No 2,991,250 July 4 1961 John F, So c olof'sky hat error appearsin ,the above nuInbredpat- It is hereby certified t F that the saidLetters Patent should read as entrequiring correction and correctedbelow In the heading to columns 1 and 2 upper right-hand g q portionafter the patent number for "Reissue July 4 1961'" read Patented July 41961 a (SEAL) Attest:

ERNEST W. sWIDE Attesting Officer I DAVID L. LADD Commissioner ofPatents

1. A METHOD OF LUBRICATING A MARINE TURBINE AND THE ASSOCIATED REDUCTIONGEARS WHICH COMPRISES APPLYING TO THE RELATIVELY MOVING PARTS THEREOF ACOMPOSITION COMPRISING A MAJOR PROPORTION OF MINERAL LUBRICATING OIL, AMINOR PROPORTION, FROM ABOUT 0.05% TO ABOUT 2%, BY WEIGHT, OF A PHENOLICANTIOXIDANT, A MINOR PROPORTION, FROM ABOUT 0.01% TO ABOUT 1%, BYWEIGHT, OF AN ANTIRUST AGENT CONSISTING OF A REACTION PRODUCT OBTAINEDBY REACTING A MONOCARBOXYLIC ACID WITH A POLYALKYLENEPOLYAMINE HAVINGONE MORE NITROGEN ATOM PER MOLECULE THAN THERE ARE ALKYLENE GROUPS INTHE MOLECULE, IN A MOLAR PROPORTION VARYING BETWEEN ABOUT 1 AND ABOUTX-1 TO 1, RESPECTIVELY, WHEREIN X REPRESENTS THE NUMBER OF NITROGENATOMS IN THE POLYALKYLENEPOLYAMINE MOLECULE, TO PRODUCE AN INTERMEDIATEPRODUCT, AND REACTING AN ALKENYL SUCCINIC ACID ANHYDRIDE WITH SAIDINTERMEDIATE PRODUCT, IN A MOLAR PROPORTION VARYING BETWEEN ABOUT X-1AND ABOUT 1 TO 1, RESPECTIVELY, THE SUM OF THE NUMBER OF MOLES OF SAIDMONOCARBOXYLIC ACID AND OF SAID ALKENYL SUCCINIC ACID ANHYDRIDE REACTEDWITH EACH MOLE OF SAID POLYALKYLENEPOLYAMINE BEING NO GREATER THAN X,AND A MINOR PROPORTION, FROM ABOUT 0.25% TO ABOUT 5.0%, BY WEIGHT, OFTRIS-(2-CHLOROPROPYL)-THIONOPHOSPHATE.